1. Field of the Invention
The present invention relates to a thermoplastic resin composition, and more particularly to a thermoplastic resin composition containing an iminated copolymer.
2. Prior Art
A copolymer prepared by graft-copolymerizing a rubber-like polymer with a mixture including an aromatic vinyl monomer, an unsaturated dicarboxylic acid anhydride and other monomers, and a blend composition including said copolymer blended with a rubber-modified copolymer have hitherto been known by Unexamined Japanese Patent Publication Nos. 42091/1973 and 96555/1979. Although these known copolymers prepared by copolymerizing unsaturated dicarboxylic acid anhydrides have high heat distortion temperatures, they tend to decompose due to chemical reactions in the presence of water at high temperature or only by subjecting to high temperature since they have acid anhydride residues in the copolymer chains derived from the unsaturated dicarboxylic acid anhydrides. For this reason, in addition to the strict limitation imposed on the injection or extrusion molding operations, the mechanical properties, particularly the impact strength, are deteriorated when the molded products are contacted with water or steam or exposed to high temperature.
U.S. Pat. No. 3,642,949 discloses a composition comprising a so-called ABS resin blended with a copolymer of an aromatic vinyl monomer and an unsaturated dicarboxylic acid anhydride or an imide thereof. However, the product made of such a composition blended with an unsaturated dicarboxylic acid anhydride or an imide derived from an unsaturated dicarboxylic acid has unsatisfactorily low impact strength.